Evaluation of the Effect of Hamao Detention Pond on Excess Runoff from the Abukuma River in 2019 and Simple Remodeling of the Pond to Increase Its Flood Control Function

Due to the recent increase in the intensity of rainstorms, the Japanese government has announced a new policy of flexible flood mitigation measures that presupposes the release of water volumes exceeding the river channel capacity onto floodplains. However, due to the limited amount of quantitative measurement data on excess runoff, it will take time to formulate planning standards for remodeling and newly constructing flood control facilities reasonable enough under current budgetary constraints. In this study, the capacity shortage of a flood detention pond was evaluated against the excess runoff from a severe 2019 flood event by combining the fragmentary measurement data with a numerical flow simulation. Although the numerical model was a rather simple one commonly used for rough estimation of inundation areas in Japan, the results were overall consistent with the observations. Next, in accordance with the new policy, an inexpensive remodeling of the detention basin, which was designed according to conventional standards, was simulated; the upstream side of the surrounding embankment was removed so that excess water flowed up onto the floodplain gradually. Numerical experiments using the simple model indicated that the proposed remodeling increased the effectiveness of flood control remarkably, even for floods greater than the 2019 flood, without much inundation damage to upstream villages.

Selected Crater and Small Caldera Lakes in Alaska: Characteristics and Hazards

This study addresses the characteristics, potential hazards, and both eruptive and non-eruptive role of water at selected volcanic crater lakes in Alaska. Crater lakes are an important feature of some stratovolcanoes in Alaska. Of the volcanoes in the state with known Holocene eruptive activity, about one third have summit crater lakes. Also included are two volcanoes with small caldera lakes (Katmai, Kaguyak). The lakes play an important but not well studied role in influencing eruptive behavior and pose some significant hydrologic hazards. Floods from crater lakes in Alaska are evaluated by estimating maximum potential crater lake water volumes and peak outflow discharge with a dam-break model. Some recent eruptions and hydrologic events that involved crater lakes also are reviewed. The large volumes of water potentially hosted by crater lakes in Alaska indicate that significant flowage hazards resulting from catastrophic breaching of crater rims are possible. Estimates of maximum peak flood discharge associated with breaching of lake-filled craters derived from dam-break modeling indicate that flood magnitudes could be as large as 103–106 m3/s if summit crater lakes drain rapidly when at maximum volume. Many of the Alaska crater lakes discussed are situated in hydrothermally altered craters characterized by complex assemblages of stratified unconsolidated volcaniclastic deposits, in a region known for large magnitude (>M7) earthquakes. Although there are only a few historical examples of eruptions involving crater lakes in Alaska, these provide noteworthy examples of the role of external water in cooling pyroclastic deposits, acidic crater-lake drainage, and water-related hazards such as lahars and base surge.

Virtual water flows and economic water productivity of Italian fair-trade: the case of bananas, cocoa and coffee

PurposeIn a globalized economic system, the role of agrifood production is to ensure at the same time both the population's livelihood and environmental resource conservation. The present study aims at expanding the debate on the potentials of the fair-trade in terms of environmental sustainability.Design/methodology/approachThe research presents a methodology divided into three phases: (1) the identification of the water footprint values associated with the production of bananas, cocoa and coffee imported from developing countries to Italy; (2) the calculation of the virtual water volumes used to produce the crops imported from developing countries to Italy through fair-trade; (3) the analysis of the economic water productivity, obtained by the fair-trade premium, for bananas, cocoa and coffee.FindingsThe results of this study identified and measured the amount of virtual water flows and water savings or losses deriving from the fair-trade of bananas, cocoa and coffee. The average virtual water flow related to the fair-trade imports in Italy amounts to 7.27 million m3 for bananas, 22,275 m3 for cocoa and 14,334 m3 for coffee. The research findings also highlight that fair-trade and the related premium ensures at the same time the achievement of social and institutional purposes but also the remuneration of virtual water used within the life cycle of the imported crops.Originality/valuePrevious scientific literature showed that fair-trade premium has commonly been used to finance environmental protection. No study has evaluated the environmental impacts associated with fair-trade, nor the monetary value associated with the natural resources exploited to produce crops to be exported. This empirical paper fills a literature gap in terms of identification, measurement and evaluation of virtual water flows along the supply chain processes of some fair-traded crops, also providing, through the economic water productivity approach, a useful tool for decision-makers.

Optimization of ‘On Farm’ Hydropriming Conditions In Wheat: Soaking Time And Water Volume Have Interactive Effects On Seed Performance

Seed priming is a simple and cost effective method to obtain a better plant stand under diverse environmental conditions. The current study was designed to determine the optimal priming duration and water volume for wheat seed. For this experiment, three wheat genotypes with distinct genetic and adaptive backgrounds were chosen. Seeds of each genotype were hydroprimed for 7 durations, i.e. 1, 2, 4, 8, 12, 16, and 20 hours, in three different water volumes, i.e. half, equal, and double volume with respect to seed weight. The control was unprimed (dry) seed. The germination characteristics and seedling vigour potential of hydroprimed seeds were evaluated in the lab by recording several parameters such as germination percentage and speed, seedling growth, and vigour indices at two different temperature levels. The results showed that optimal duration for hydropriming of wheat seed is 12 hours with an equal volume with respect to original seed weight, closely followed by 8 hours with double volume. Reduction in seed performance was observed at 16 and 20 hours priming particularly at double volume treatment. Effect of temperature on seed germination showed improvement in seedling vigour at 25°C when compared to 20°C, although germination percentage decreased slightly. Volume of water and priming duration showed significant interactive effects demonstrating that a higher volume can give equivalent results at a shorter duration and vice versa.

Hazardous Substances and their Effects on Drinking Water Sources

Drinking water cannot be produced from every raw surface or groundwater in the European Union countries. The source must meetthe set criteria for the raw water quaility. At present time, drinking water sources meet these requirements. However in the climatechange period, accompanied in particular by long-term loss of water volumes, the set limit values for individual categories of raw watermay be frequently exceeded. Human society must be prepared for this threat and take legislative and technical-operational steps in atimely manner to eliminate the risk. This paper deals with the issue in the basic scope and declares what producers and steps can beused in practice to increase the resilience of water resources to the expected change in the water quality

Interpreting the Manning Roughness Coefficient in Overland Flow Simulations with Coupled Hydrological-Hydraulic Distributed Models

There is still little experience on the effect of the Manning roughness coefficient in coupled hydrological-hydraulic distributed models based on the solution of the Shallow Water Equations (SWE), where the Manning coefficient affects not only channel flow on the basin hydrographic network but also rainfall-runoff processes on the hillslopes. In this kind of model, roughness takes the role of the concentration time in classic conceptual or aggregated modelling methods, as is the case of the unit hydrograph method. Three different approaches were used to adjust the Manning roughness coefficient in order to fit the results with other methodologies or field observations—by comparing the resulting time of concentration with classic formulas, by comparing the runoff hydrographs obtained with aggregated models, and by comparing the runoff water volumes with observations. A wide dispersion of the roughness coefficients was observed to be generally much higher than the common values used in open channel flow hydraulics.

Development of an NCAM motorized GRAIN GRUEL (Soy Bean) sieving machine

A survey carried out on conventional or traditional method of sieving wet grains showed that the method consumes time, energy, has low output and efficiency and is also hazardous to health due to low level of hygiene involved. A motorized grain gruel machine was developed at the National Centre for Agricultural Mechanization (NCAM), Ilorin Nigeria. The machine consists of four major units which are hopper, seiver, separator and the discharge unit. The machine’s performance was evaluated at different water volumes (16.5, 18.5 and 20.5 liters) and at three different operating speeds namely 65.3 rpm, 115.0 rpm and 126.0 rpm. The parameters evaluated are; sieving efficiency, through put and output capacity. The data were analyzed using the New Duncan multiple range test (Post Hoc Test) method and linear regression model was used to establish the relationship between the independent variables with the dependent variable, which was optimized using pulp in python version 2.9 frame work. Results show that the machine performed higher at 20.5litres and 126 rpm to a maximum sieving efficiency of 85.08% and 86.48% respectively, but was optimized to the range of 88.35-92.5% in sieving efficiency and 19.42-23.42kg/hr in output capacity. Also the analysis showed that water volume used had more significant effect on the efficiency and other variables such as the throughput and the output capacity respectively, than the operation speed. It was concluded from the results that the machine saved time and energy, reduced material wastage and hazards and therefore is more efficient than the conventional method. It is recommended that further evaluations should be carried out on the machine using a wider variety and species of grains samples.

Towards environmental DNA-based bioassessment of freshwater reservoirs with small volumes of water: robust molecular protocols

Bioassessment of freshwater quality via eDNA is rapidly developing into a powerful alternative to traditional methods involving collecting, sorting, and identifying macroinvertebrates based on morphology. Particularly attractive would be methods that can use remote-controlled boats for sampling because it would allow for cost-effective, and frequent monitoring at multiple sites. The latter will be particularly important for tropical reservoirs that require year-around surveillance. We here optimize molecular protocols for capturing reservoir-specific differences in metazoan communities based on small water volumes (15 mL). The optimization is based on samples from two freshwater reservoirs with very different water qualities ("reservoir signal"). Each reservoir was sampled at three sites ("biological replicates"). For each water sample, the DNA was extracted twice ("technical replicates"). We then tested how much DNA template (0.1 ng to 15 ng) and how many PCR cycles (25 or 35) minimized variance between technical replicates. We find that 15 mL is sufficient for capturing the reservoir signal regardless of sampling time, template amounts, or PCR cycle numbers. Indeed, extrapolation from our results suggests that <1 mL would be sufficient because only 17 of 59 metazoan mOTUs (mainly planktonic crustaceans and rotifers) detected with a 313bp COI minibarcode were shared. We find that the use of 35 PCR cycles significantly lowered the number of detected species and that template amounts <0.5 ng yielded somewhat higher variance between technical replicates. Despite extensive trials, the variance between technical replicates remained high (Bray-Curtis: 5-20%; Jaccard: 10-40%) and we predict that it will be difficult to reduce this variance further. However, the overall reservoir differences are so strong that all biological and technical replicates can be correctly assigned.

Gravity as a tool to improve the hydrologic mass budget in karstic areas

Monitoring the water movements in karstic areas is a fundamental but challenging task due to the complexity of the drainage system and the difficulty in deploying a network of observations. Gravimetry offers a valid complement to classical hydrologic measurements in order to characterize such systems in which the recharge process causes temporarily accumulation of large water volumes in the voids of the epi-phreatic system. We show an innovative integration of gravimetric and hydrologic observations that constrains a hydrodynamic model of the Škocjan cave system (Slovenia). We demonstrate how the inclusion of gravity observations improves water mass budget estimates for the Škocjan area based on hydrological observations only. Finally, the detectability of water storage variations in other karstic contexts is discussed with respect to the noise performances of spring and super-conducting gravimeters.

Space use and parental care behaviour in Andinobates claudiae (Dendrobatidae)

The selection of habitats with potential reproductive resources may maximize individual reproductive success and overall fitness. Dendrobatid frogs display remarkable parental care which is associated with water bodies (phytotelmata) contained in plants with characteristics that are important to offspring survival. It has been shown that the size of phytotelmata is a key factor that drove the divergence in parental care patterns in poison frogs and that the distribution of reproductive resources can influence space use in these species. Here, we investigated parental care strategies and the influence of reproductive resource distribution on space use patterns in a wild population of Andinobates claudiae in Bocas del Toro, Panama. We identified the phytotelmata characteristics that predict tadpole deposition and analysed the association between the spatial distribution of phytotelmata and spatial use of males and females. Our observations showed that this species mates polygamously and exhibits male parental care. We found that male frogs have smaller kernel density home ranges and core areas compared to females, and that space use is related to the density of Heliconia plants whose axil cavities are used for tadpole rearing. Furthermore, we found that tadpoles were more frequently found in phytotelmata that were at lower heights and contained larger water volumes. Fathers invested time inspecting multiple cavities and travelled further than predicted from their territories to find suitable deposition sites. Our observations suggest a selective choice of phytotelmata regarding tadpole deposition, where distribution and quality of cavities might influence parental care decisions.